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Main Authors: Glogić, Irfan, Hofmanová, Martina, Lange, Theresa, Luongo, Eliseo
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2501.17032
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author Glogić, Irfan
Hofmanová, Martina
Lange, Theresa
Luongo, Eliseo
author_facet Glogić, Irfan
Hofmanová, Martina
Lange, Theresa
Luongo, Eliseo
contents We consider the focusing power nonlinearity heat equation \begin{equation}\label{Eq:Heat_abstract}\tag{NLH} \partial_t u -Δu = |u|^{p-1}u, \quad p>1, \end{equation} in dimensions $d \geq 3$. It is well-known that if $p$ is large enough then \eqref{Eq:Heat_abstract} is unconditionally locally well-posed in $L^q(\mathbb{R}^d)$ for $q \geq d(p-1)/2$. We prove that this result is optimal in the sense that uniqueness of local solutions fails when $q < d(p-1)/2$ as long as $p < p_{JL}$, where $p_{JL}$ stands for the Joseph-Lundgren exponent. Our proof is based on the method that Jia-Šverák proposed in \cite{JiaSve15} to show non-uniqueness of Leray solutions to incompressible 3d Navier-Stokes equations. In particular, we rigorously verify for \eqref{Eq:Heat_abstract} the (analogue of the) spectral assumption made in \cite{JiaSve15}. To our knowledge, this is the first rigorous implementation of the Jia-Šverák method to a nonlinear parabolic equation without forcing.
format Preprint
id arxiv_https___arxiv_org_abs_2501_17032
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Non-uniqueness of mild solutions to supercritical heat equations
Glogić, Irfan
Hofmanová, Martina
Lange, Theresa
Luongo, Eliseo
Analysis of PDEs
Spectral Theory
We consider the focusing power nonlinearity heat equation \begin{equation}\label{Eq:Heat_abstract}\tag{NLH} \partial_t u -Δu = |u|^{p-1}u, \quad p>1, \end{equation} in dimensions $d \geq 3$. It is well-known that if $p$ is large enough then \eqref{Eq:Heat_abstract} is unconditionally locally well-posed in $L^q(\mathbb{R}^d)$ for $q \geq d(p-1)/2$. We prove that this result is optimal in the sense that uniqueness of local solutions fails when $q < d(p-1)/2$ as long as $p < p_{JL}$, where $p_{JL}$ stands for the Joseph-Lundgren exponent. Our proof is based on the method that Jia-Šverák proposed in \cite{JiaSve15} to show non-uniqueness of Leray solutions to incompressible 3d Navier-Stokes equations. In particular, we rigorously verify for \eqref{Eq:Heat_abstract} the (analogue of the) spectral assumption made in \cite{JiaSve15}. To our knowledge, this is the first rigorous implementation of the Jia-Šverák method to a nonlinear parabolic equation without forcing.
title Non-uniqueness of mild solutions to supercritical heat equations
topic Analysis of PDEs
Spectral Theory
url https://arxiv.org/abs/2501.17032